Project Summary/Abstract The transient receptor potential (TRP) superfamily of non-selective cation channels play critical roles in diverse physiological processes including the perception of light, temperature, pressure, and pain. In previous genetic studies, we have discovered that mutation of a member of the melastatin-related TRP-channels (TRPM3) underlies an inherited form of pediatric cataract that is variably associated with glaucoma and anterior segment defects. In this proposal, we will investigate the role of TRPM3 in lens development and cataract pathobiology using gene-edited mice and cell-lines by addressing three specific aims. In aim-1, we will characterize lens TRP-channel transcript splice-variants by means of RNA deep-sequencing and the calcium channel properties of lens TRPM3 isoforms using fluorometric calcium imaging techniques. In aim-2, we will characterize the effects of TRPM3 dysfunction and deficiency on lens cation status, water content, and calcium influx properties using a combination of atomic absorption spectrometry and calcium imaging techniques. In aim-3, we will characterize the effects of TRPM3 dysfunction and deficiency on lens morphogenesis and gene expression using differential immuno-fluorescence microscopy and RNA deep-sequencing techniques, respectively. Results from these studies will provide new insights regarding the role of TRP-channels in lens growth, cation homeostasis, calcium dynamics, and pathophysiology within the context of pediatric cataract ? a clinically important risk factor for lifelong visual impairment. More broadly, these studies will contribute to an understanding of TRP-channel function and dysfunction in other eye tissues (e.g., iris, ciliary body) and diseases (e.g., glaucoma, anterior eye defects), respectively.